package com.ctcemti.mdm.framework.filter;


import com.ctcemti.mdm.common.result.Result;
import com.ctcemti.mdm.common.result.ResultEnum;
import com.ctcemti.mdm.common.util.JWTUtil;
import com.ctcemti.mdm.common.util.OutHtml;
import com.ctcemti.mdm.framework.shiro.JWTToken;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMethod;
import tk.mybatis.mapper.util.StringUtil;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


/**
 * @ClassName JWTFilter
 * @Description jwt用于拦截
 * @Author bxf
 * @Date 11:38 2019/8/11
 * @Version V1.0
 **/
@Slf4j
@Component
public class JWTFilter extends BasicHttpAuthenticationFilter {

    @Value("${loginRealmName}")
    private String loginRealmName;
    /**
     * 判断用户是否想要登入。
     * 检测header里面是否包含Authorization字段即可
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        System.out.println("进入JWTFilter的isLoginAttempt方法"+((HttpServletRequest)request).getRequestURI());
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        return isvalid(authorization);
    }

    public boolean isvalid(String token){
        if(StringUtil.isEmpty(token)){
            return false;
        }else{
            return JWTUtil.verify(token);
        }
    }

    /**
     * 执行登录
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String authorization = httpServletRequest.getHeader("Authorization");
        JWTToken token = new JWTToken(authorization);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(token);
        // 如果没有抛出异常则代表登入成功，返回true
        return true;
    }

    /**
     * 这里我们详细说明下为什么最终返回的都是true，即允许访问
     * 例如我们提供一个地址 GET /article
     * 登入用户和游客看到的内容是不同的
     * 如果在这里返回了false，请求会被直接拦截，用户看不到任何东西
     * 所以我们在这里返回true，Controller中可以通过 subject.isAuthenticated() 来判断用户是否登入
     * 如果有些资源只有登入用户才能访问，我们只需要在方法上面加上 @RequiresAuthentication 注解即可
     * 但是这样做有一个缺点，就是不能够对GET,POST等请求进行分别过滤鉴权(因为我们重写了官方的方法)，但实际上对应用影响不大
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        boolean flag = true;
        if (isLoginAttempt(request, response)) {
            try {
                executeLogin(request, response);
            } catch (Exception e) {
                response403(request, response);
            }
        }else{
            response403(request, response);
        }
        return flag;
    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", "*");
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));


        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }

    /**
     * 将非法请求跳转到 /403
     */
    private void response403(ServletRequest req, ServletResponse resp) {
        try {
            HttpServletResponse httpServletResponse = (HttpServletResponse) resp;
            String url = ((HttpServletRequest) req).getRequestURI();
            if("XMLHttpRequest".equals(((HttpServletRequest) req).getHeader("X-Requested-With"))){

                httpServletResponse.setCharacterEncoding("UTF-8");
                httpServletResponse.setContentType("application/json; charset=utf-8");
                OutHtml.writeJson(httpServletResponse,new Result<>(ResultEnum.ZTSJ_1101,null));


            }else{
            	httpServletResponse.sendRedirect(loginRealmName);
            }
        } catch (IOException e) {
            log.error(e.getMessage());
        }
    }
}
